Opioids are prescription painkillers used to treat moderate-to-severe pain. Not all opioids are the same, differing in what they do to your body, and how they move throughout your body.

Opioids in New Zealand are divided into two different groups - weak and strong. Weak opioids are prescribed when other painkillers have not worked for the patient - they include tramadol, dihydrocodeine and codeine.

Strong opioids may be trialled when weak opioids have not had any beneficial effect. Strong opioids include morphine, oxycodone, methadone, fentanyl and pethidine.

How it works

Although different opioids can have different effects, they all control pain relief by binding to your body's opioid receptors. Opioids activate the receptors located in the brain, spinal cord, and other organs that are associated with feeling pain or pleasure. After taking opioids for an extended period of time, the brain adapts to the drug. This diminishes the brain's sensitivity, making it harder for a patient to feel any pain relief or pleasure from anything except the drug.

Long-term/short-term side effects

Many opioid users report unpleasant side effects, such as constipation, nausea, sleepiness and dizziness. Long-term use of opioids can have serious consequences, such as hypogonadism, adrenal insufficiency and abnormal pain sensitivity. A major concern about opioids is around dependence. A patient can suffer from substance use disorder even if using opioids as they were prescribed. Dependence can appear within just one month of use. In high enough doses, opioids can lead to respiratory failure, coma and death. Prescription fentanyl can reportedly be up to 50 times more potent than the illegal drug heroin. A teaspoon of powdered fentanyl can kill up to 1000 people.

Newshub has cross-checked the medical analysis in this article with Dr Samantha Murton, President of The Royal New Zealand College of General Practitioners.

View post:
Explained: What painkillers do to the human body - Newshub